420 EXTERNAL ANATOMY OF INSECTS, 
the ligula of Fabricius as the labium, and called the /a- 
bium of that author the mentwm*; but afterwards he gave 
the name of Jabium to the whole middle piece of the 
lower apparatus of the mouth—calling the upper piece, 
with Fabricius, the Jigula, and retaining the denomina- 
tion of mentum for the lower’. 
If the circumstances of the case are duly considered, 
I think you will be convinced that the term under-lip, 
or labium, should be confined to that part which the 
learned Dane so named. Fer I would ask, Which is 
the part on the under-side of the head that is the anta- 
gonist, if I may so speak, of the upper-lip or labrum ? 
Is it not that organ which, when the mouth is closed, 
meets that part, and in conjunction with it shuts all in? 
Now in numerous insects, particularly the Lamellicorn 
beetles (Scarabeus and Lucanus L.), this is precisely the 
case. In the Predaceous beetles, indeed, (Adephagana) 
the under-lip does not meet the upper, to close the mouth 
and shut in the tongue; neither can the tongue be said 
so to do, but only, from some circumstances connected 
with its manner of taking its food, it is requisite that the 
last-mentioned organ should not be retractile or covered; 
but its miscalled mentum is still the analogue of that 
part which helps to close the mouth in the former tribe. 
Should not this, therefore, which so often performs the 
office, be distinguished by the name of a lip? Again, is 
it not rather incongruous to consider that organ which 
confessedly more or less performs the office of a tongue, 
as a part of the zp? Though it often wears that ap- 
pearance, yet I believe, if the matter is thoroughly and 
* Gen. Crustac. et Ins.i1. 180. ” N. Dict. d’ Hist. Nat. iy. 246. 
